16 hp b&s opposed twin problem

so i got this motor for my cub project and it ran great. i didnt have time to work on it and put it under my shed and apparrently my shed leaks really bad and water got in the motor, and now its locked up bad, any advice? it was always hard to start with a lawn mower battery almaost always had to jump it from the truck, actually had to hook it straight to the starter a few times.

It will atleast need to be torn down.

If you are lucky, all you will need to do is a quick hone on the cylinder walls, and a little work on the piston and rings. if you aren't lucky, the crank, or connecting rod bearings are siezed, and it will need major help.

It may be possible to break it free, using a little wd 40 and some elbow grease and patience.

Pull the plug and find the best penetrating oil you can afford. Drain the oil, and set the engine up to the spark plug is pointed up.

Fill the cyclinder to the top and let it sit for a few days or a week or two even.

Put a big wrench on the crankshaft nut, or find some way to turn over the ngine with a wrench.

See if you can break it free.

If it frees up it you only need to do the hone and deglaze the rings. Then you will basically have to do a break in on it to reseat the rings.

If not. You got big problems
. And it need to come apart.

Dont't get prematurely stressed. I've got an engine here that sat for over 30 years. and all it needed was a tweak with a wrench on the crank.
It runs great. i've never torn it down, but....

Its a honda bike engine, much better quality the the usual cheapo commercial engines in these tractors.

Twin opposed cylenders, no matter how new or old, are always a bear to crank over - twice the mass to move - youll want at LEAST a 600 or more CCA battery to effectively crank it over.

Another thing id do is to clean/check the starter motor - they take a ton of abuse.

Id pull the heads off and check the combustion chambers - then id put em back together, and soak the snot of of them with PB blaster and let it soak for at least a day or so. If water is in the motor - it wont turn over and hydro lock.

I have a '86 18HP opposed twin horizontal shaft briggs motor - thing was full to the top of the carb with rusty water when i got it - water hadnt gotten into the oil, so that was ok . I pulled the heads to let the water drain, i cleaned everything up,, took the carb apart, cleaned the starter, added new battery cables ( starter was on the bottom of the motor) - soaked it for a couple days with PB, put it back together and it fired on the 2nd turn of the key. It still runs good today actually.

thanks ill try soaking it, i have a video on youtube of it running, the guy i got it from had it on a go kart and put t 2 in dia. exhaust pipe on it so it sounds good, lol if that dont work im starting tech school in january, going to be a machinist, so ill probally bore it out a lil if i have to, im thinking about boring out a 18 v-twin im getting

Good thing about vtwins is they can have tons of upgrades - like roller rockers, upgrade valve springs - if its properly modifed with speed parts it can make a ton of horsepower.

I saw some racing tractors with 20HP v twins bored and modded to run in the 70/90HP range - alot of motor on a lawntractor.

I had the same problem. I man-handled it and freed the seized cylinder. I took the motor apart. It had metal all in the motor cause of the seized cylinder. I honed out the cylinder. cleaned up the motor. Put it back together. When starting it back up be careful. Mine was running and it tryed to lock up. I started it again and never had a problem with it. Just make sure to pre-oil the cylinders and parts. Hope this helps.

thanks yall as soon as i can ime work on it but i juast aint got the time right now lol

thanks for the help i got her apart then cleaned and now she is working again, only problem is i have trouble starting it with a lawn mower battery any suggestions?

I use a car battery

Twins need a bigger battery then a normal single cylender - id suggest at least 500CCA ( normal ones run around 350CCA).

It has twice as much mass to turn over, and using a larger battery will last longer.

had to crank it before, jump it from my truck lol i have a vid of it on youtube, my username there is the same as on here, i think i put a vid of it on here somewhere but aint sure lol

i have a vid of it runnin before it locked up lol its under ih cub build in project builds

I had the same problem with the starter. I had it hooked up to my dads f350 (which has two batterys)

and it still wouldnt start I ended up buying new starter 90$ it worked fine on any lawn mower battery

put penetrating oil or diesel down the cylinder to free it up

If its a completely hard to turn over, dont kill yourself on the battery, wether or not my next few words are good for the parts it uses is a story on it own. Pull a spark plug out, and turn it over like that, if should start rather easily like this, but DO NOT DRIVE IT LIKE THIS, OR USE ANY THROTTLE AT ALL! It will shoot gas and everything else. When it turns over, put the plug in using a socket extender (easier to use like this,) and the right socket and screw it in hand tight THEN use a socket wrench. put the boot on and done.